Small optimizations; run scripts with utf-8 encoding

* Avoid logging stack traces with validation errors
  It's OK to just print the string representation of the exception when
  eventlogging-processor errors occur; the stack trace is not valuable in such
  cases.
* Run scripts with utf-8 as the system encoding
* Run with -OO

Change-Id: Ib213a31411063dbdbf5798d490f142403b0bbecb